The Big Dance could turn into a Mosh Pit and, as a result, the National Invitation Tournament, the oldest college basketball tournament in the nation, could be phased out as the NCAA is poised to make monumental changes to March Madness, several sources told The Post.

The NCAA has been in high-level meetings for several weeks with officials at CBS, which currently owns the television rights to the NCAA tournament, and ESPN, which is likely to outbid CBS for the rights to the tournament.

If that happens, the NCAA tournament will expand to 96 teams, leaving no place for the Postseason NIT. The NCAA owns both tournaments.

Also, the NIT Season Tip-Off Tournament would leave the city. The Tip-Off will become known as the First Four tournament to be played in the same venue that hosts the Final Four the following spring.

In order to offset the costs of whichever network wins the rights to the NCAA tournament, the Big Dance will expand to 96 teams for the 2011 tournament. The NIT will be a casualty, said several sources.

The NCAA is poised to opt out of its $6 billion, 11-year TV deal with CBS, which runs through the 2013 tournament. If the NCAA remains with CBS for the duration of the deal, it will receive $545 million annually.

If the NCAA opts out, it could get a bigger deal and a larger field, but it would find itself battling for bucks against the NFL, which also will have its TV deals up in 2011. Either way, the NIT dies after this year or after 2013 because it is not a money maker.

Greg Sheehan, senior vice president of basketball and business for the NCAA, did not immediately return a call from The Post. Joel Fisher, senior vice president of properties for the Garden, also did not immediately return calls.

If the NCAA goes ahead with the changes, this year’s Postseason NIT will be the final one. The NIT was founded in 1938. St. John’s has won it six times. Penn State won it last year.

When the financial climate went south more than a year ago, it seemed unlikely that the NCAA would void the final three years of its agreement with CBS. But the thinking has changed as some feel the worst is over.

ESPN — with platforms such as ESPN2, ESPNU and ESPN 360, along with ABC — and Fox were outbid by CBS in the last deal. The multiple platforms could be key in landing a 96-team tournament.

Most college basketball coaches have spoken out against expansion, although Syracuse coach Jim Boeheim has been in favor. March Madness has become a golden television property, which, like the Super Bowl, has become a part of America sports culture.

“You’ve added about 70 schools since the last time you expanded the tournament,” Boeheim said last month on ESPN radio in Syracuse. “Most pro sports, more than half of the teams qualify for the playoffs. In college basketball it’s what, one-fifth? You’d think we’d figure out a way to get this thing expanded a little bit.”

The field was expanded from 48 teams to 64 in 1985, and a 65th team was added in 2001, when the number of automatic bids went from 30 to 31.